In U.S. patent application Ser. No. 11/697,622, filed 6 Apr. 2007 (hereinafter the “'622 Application”), which application is assigned to the assignee of the present invention and incorporated herein by reference, an improved polishing pad for CM P and other applications was described. The polishing pad described in the '622 Application, embodiments of which are illustrated as pad 300 in FIGS. 1A-1B, includes a guide plate 308 having affixed thereto a compressible under-layer 316. An optional porous slurry distribution layer 304 may be affixed to the other side of the guide plate. A plurality of polishing elements 306 protrude through the guide plate 308 so as to be maintained in planar orientation with respect to one another and the guide plate.
The polishing elements 306 are affixed to the compressible under-layer 316 (or to a housing), with each polishing element protruding In use, the polishing pad 300 is placed on top of the polish table 318, which rotates relative to the wafer being polished, and the polishing elements of the polishing pad make contact (typically under pressure) with a wafer 320 at a contact surface. If used, slurry distribution material 304 provides flow control in the slurry pathways between polishing elements 306.
The foundation of the polishing pad described in the '622 Application is the guide plate 308, which provides lateral support for the polishing elements 306. The guide plate includes holes to accommodate each of the polishing elements 306, thus leaving the polishing elements free to move in a vertical direction with respect to their long axis.